Explore the vast range of titles available.

I examine the introduction of an online shopping service by a large supermarket chain also operating a network of brick-and-mortar stores. The establishment of the Internet channel led to a 13 percent increase in overall revenues, with limited cannibalization of traditional sales. I study the mechanisms underlying this result, focusing on two areas. First, I demonstrate the importance of the reduction of customers' travel costs in the attraction of new business. Second, I provide some evidence that revenues increase more in markets where the chain faces more competitors, suggesting that the online channel can help divert business from rival supermarkets.

This work investigates the effectiveness of deep neural networks within the realm of battery charging. This is done by introducing an innovative control methodology that not only ensures safety and optimizes the charging current, but also substantially reduces the computational complexity with respect to traditional model-based approaches. In addition to their high computational costs, model-based approaches are also hindered by their need to accurately know the model parameters and the internal states of the battery, which are typically unmeasurable in a realistic scenario. In this regard, the deep learning-based methodology described in this work was been applied for the first time to the best of the authors’ knowledge, to scenarios where the battery’s internal states cannot be measured and an estimate of the battery’s parameters is unavailable. The reported results from the statistical validation of such a methodology underline the efficacy of this approach in approximating the optimal charging policy.

This paper compares consumers' brand exploration when shopping online versus in a brick-and-mortar store. I use a new scanner dataset to compare the behavior of households shopping online and in-store at the same chain, for identical items and prices. I find that brand exploration is more prevalent in-store. My model quantifies the role of features of e-commerce, like the existence of \"favorites lists\" and the difficulty in verifying item quality. Limited exploration online implies higher barriers to entry on the Internet channel. Counterfactual exercises suggest that online advertising could make the Internet channel more competitive.

Anuran amphibians (frogs and toads) typically have a complex life cycle, involving aquatic larvae that metamorphose to semi-terrestrial juveniles and adults. However, the anuran olfactory system is best known in Xenopus laevis, an animal with secondarily aquatic adults. The larval olfactory organ contains two distinct sensory epithelia: the olfactory epithelium (OE) and vomeronasal organ (VNO). The adult organ contains three: the OE, the VNO, and a “middle cavity” epithelium (MCE), each in its own chamber. The sensory epithelia of Xenopus larvae have overlapping sensory neuron morphology (ciliated or microvillus) and olfactory receptor gene expression. The MCE of adults closely resembles the OE of larvae, and senses waterborne odorants; the adult OE is distinct and senses airborne odorants. Olfactory subsystems in other (non-pipid) anurans are diverse. Many anuran larvae show a patch of olfactory epithelium exposed in the buccal cavity (bOE), associated with a grazing feeding mode. And other anuran adults do not have a sensory MCE, but many have a distinct patch of epithelium adjacent to the OE, the recessus olfactorius (RO), which senses waterborne odorants. Olfaction plays a wide variety of roles in the life of larval and adult anurans, and some progress has been made in identifying relevant odorants, including pheromones and feeding cues. Increased knowledge of the diversity of olfactory structure, of odorant receptor expression patterns, and of factors that affect the access of odorants to sensory epithelia will enable us to better understand the adaptation of the anuran olfactory system to aquatic and terrestrial environments.

Typically, animal mitochondria have very compact genomes, with few short intergenic regions, and no introns. Hence, it may seem that there is little space for unknown functions in mitochondrial DNA (mtDNA). However, mtDNA can also operate through RNA interference, as small non coding RNAs (sncRNAs) produced by mtDNA have already been proposed for humans. We sequenced sncRNA libraries from isolated mitochondria of Ruditapes philippinarum (Mollusca Bivalvia) gonads, a species with doubly uniparental inheritance of mitochondria, and identified several putative sncRNAs of mitochondrial origin. Some sncRNAs are transcribed by intergenic regions that form stable stem-hairpin structures, which makes them good miRNA-like candidates. We decided to name them small mitochondrial highly-transcribed RNAs (smithRNAs). Many concurrent data support that we have recovered sncRNAs of mitochondrial origin that might be involved in gonad formation and able to affect nuclear gene expression. This possibility has been never suggested before. If mtDNA can affect nuclear gene expression through RNA interference, this opens a plethora of new possibilities for it to interact with the nucleus, and makes metazoan mtDNA a much more complex genome than previously thought.

For decades, the evolutionary role of melanism in reptiles has been highly debated. According to the thermal melanism hypothesis, melanistic phenotypes should provide thermal advantages, thus positively impacting various biological aspects of these individuals. Nevertheless, these benefits seem to be countered by environmental constraints and predatory pressure. Here, we mapped for the first time the distribution of the melanistic phenotypes in the highly polymorphic asp viper (Vipera aspis). We focused our research effort on the Italian peninsula, where this species reaches its highest level of taxonomic diversity with three currently described subspecies. Furthermore, we investigated via bioclimatic niche modelling, the influence of a wide array of bioclimatic variables on the distribution of melanism in Italian asp vipers. In general, our results seem to support the implications of the thermal melanism hypothesis, highlighting the central influence of mean annual temperature and elevation on the geographic distribution of melanistic V. aspis. At the finest scale, our analyses have highlighted a distinction in bioclimatic niches among the three assessed subspecies. However, further fine-scale investigations are needed in order to exclude the potential influence of latitude and elevation on the observed the intersubspecific bioclimatic niche segregation pattern.

Learning and remembering an opponent and the characteristics of a previous encounter may allow individuals to modify their behavior based on that acquired information. In the present study, using a long-term memory paradigm associated with social interactions, we aimed to evaluate the neuronal activation underlying individual recognition and memory of a previous agonistic encounter in male zebrafish. By quantifying the immediate-early gene c-fos, we compared neuronal activation across different telencephalic nuclei of the social decision-making network. Two dorsal nuclei, the medial (Dm) and the lateral (Dl), and two ventral nuclei, the ventral (Vv) and the dorsal (Vd), were evaluated by quantifying c-fos protein by immunohistochemical techniques. Two agonistic encounters between the same pair of opponents were performed. The number of c-fos–immunopositive cells was quantified immediately after the second encounter in fish that either exhibited behavioral evidence of remembering their opponent, behaved as if they did not recognize the opponent due to treatment with an amnesic agent after the first encounter, or belonged to a no-agonistic-encounter group with no physical interaction. We found that the Vv nucleus showed lower activation in individuals who were not exposed to physical interaction than in those who participated in agonistic encounters. The Dl nucleus showed a higher activation only in individuals who would face an unremembered opponent, but not in those who recognized the opponent. Our findings provide a first step toward understanding the neuronal processes underlying opponent recognition and retrieval of prior agonistic experience.

Background A single circular mitochondrial (mt) genome is a common feature across most metazoans. The mt-genome includes protein-coding genes involved in oxidative phosphorylation, as well as RNAs necessary for translation of mt-RNAs, whose order and number are highly conserved across animal clades, with few known exceptions of alternative mt-gene order or mt-genome architectures. One such exception consists of the fragmented mitochondrial genome, a type of genome architecture where mt-genes are split across two or more mt-chromosomes. However, the origins of mt-genome fragmentation and its effects on mt-genome evolution are unknown. Here, we investigate these origin and potential mechanisms underlying mt-genome fragmentation, focusing on a genus of booklice, Liposcelis , which exhibits elevated sequence divergence, frequent rearrangement of mt-gene order, and fragmentation of the mt genome, and compare them to other Metazoan clades. Results We found this genus Liposcelis exhibits very low conservation of mt-gene order across species, relative to other metazoans. Levels of gene order rearrangement were, however, unrelated to whether or not mt-genomes were fragmented or intact, suggesting mitochondrial genome fragmentation is not affecting mt-gene order directly. We further investigated possible mechanisms underpinning these patterns and revealed very high conservation of non-coding sequences at the edges of multiple recombination regions across populations of one particular Liposcelis species, supportive of a hypothesis that mt-fragmentation arises from recombination errors between mt-genome copies. We propose these errors may arise as a consequence of a heightened mutation rate in clades exhibiting mt-fragmentation. Consistent with this, we observed a striking pattern across three Metazoan phyla (Arthropoda, Nematoda, Cnidaria) characterised by members exhibiting high levels of mt-gene order rearrangement and cases of mt-fragmentation, whereby the mt-genomes of species more closely related to species with fragmented mt-genomes diverge more rapidly despite experiencing strong purifying selection. Conclusions We showed that contrary to expectations, mt-genome fragmentation is not correlated with the increase in mt-genome rearrangements. Furthermore, we present evidence that fragmentation of the mt-genome may be part of a general relaxation of a natural selection on the mt-genome, thus providing new insights into the origins of mt-genome fragmentation and evolution.

The glomerular array in the olfactory bulb of many vertebrates is segregated into molecularly and anatomically distinct clusters linked to different olfactory functions. In anurans, glomerular clustering is so far only described in . We traced olfactory projections to the bulb in tadpoles belonging to six distantly related anuran species in four families (Pipidae, Hylidae, Bufonidae, Dendrobatidae) and found that glomerular clustering is remarkably conserved. The general bauplan consists of four unequally sized glomerular clusters with minor inter-species variation. During metamorphosis, the olfactory system undergoes extensive remodeling. Tracings in metamorphotic and juvenile and suggest a higher degree of variation in the glomerular organization after metamorphosis is complete. Our study highlights, that the anatomical organization of glomeruli in the main olfactory bulb (MOB) is highly conserved, despite an extensive ecomorphological diversification among anuran tadpoles, which suggests underlying developmental constraints.

In the last decade, the techniques of news aggregation and summarization have been increasingly gaining relevance for providing users on the web with condensed and unbiased information. Indeed, the recent development of successful machine learning algorithms, such as those based on the transformers architecture, have made it possible to create effective tools for capturing and elaborating news from the Internet. In this regard, this work proposes, for the first time in the literature to the best of the authors’ knowledge, a methodology for the application of such techniques in news related to cryptocurrencies and the blockchain, whose quick reading can be deemed as extremely useful to operators in the financial sector. Specifically, cutting-edge solutions in the field of natural language processing were employed to cluster news by topic and summarize the corresponding articles published by different newspapers. The results achieved on 22,282 news articles show the effectiveness of the proposed methodology in most of the cases, with 86.8% of the examined summaries being considered as coherent and 95.7% of the corresponding articles correctly aggregated. This methodology was implemented in a freely accessible web application.